1. Field of the Invention
The present invention relates to a method of heat-treating a charge of metallic workpieces, or of a single workpiece, in a vessel which can be closed off and evacuated. Furthermore, the present invention relates to a vacuum furnace for carrying out such a method. This furnace includes a steel vessel which can be closed off, and which contains an inner heating chamber for receiving the charge. Heating means are provided within the heating chamber, and a gas fan and a gas guiding arrangement are provided for producing a gas circulation through the heating chamber.
2. Description of the Prior Art
Vacuum furnaces of this general type are known. When a charge is heated in the vacuum, the energy transfer is effected nearly exclusively by radiation. In such a situation, the energy which can be transmitted is a function of the temperature. In practice, this means that heating to about 750.degree. C. is effected very slowly. Furthermore, shadow effects occur which make the desired uniform heating of the charge difficult to achieve.
An object of the present invention is to provide a method, for heat-treating a charge, which makes possible a more rapid heating, and with which at the same time there is achieved a uniform distribution of heat within the charge.
A further object of the present inventionis to provide a vacuum furnace which is suitable for carrying out the inventive method.